# all() function in Python

## Introduction

The `all()` function returns `True` if all elements in the given iterable are true. If not, it returns `False`.

The `all()` function takes a single parameter `iterable` and returns `True` if all elements in an iterable are true or `False` if any element in an iterable is false.

The syntax of the `all()` function is:

```python
all(iterable)

```

where iterable can be any iterable (list, tuple, dictionary, etc.) which contains the elements.

Since `all()` can return True and False depending upon the conditions, we can summarise its return value in the following table:

| Condition                                        | Return Value |
| ------------------------------------------------ | ------------ |
| All values are `True`                            | `True`       |
| All values are `False`                           | `False`      |
| One of the values in `True` (others are `False`) | `False`      |
| One of the values is `False` (others are `True`) | `False`      |
| Empty Iterable                                   | `True`       |

## Working of `all()` for lists, tuples, and sets

```python
## All values are true
list1 = [1, 2, 3, 4, 5]
print(all(list1))

## All values are false
list2 = [0, False]
print(all(list2))

## One value is false(i.e. 0)
list3 = [1, 2, 3, 4, 0]
print(all(list3))

## One value is true(i.e. 1)
list4 = [0, False, 1]
print(all(list4))

## Empty iterable
list5 = []
print(all(list5))

```

Output:

```bash
True
False
False
False
True

```

## Working of `all()` for strings

```python
string1 = "I am learning Python built-ins"
print(all(string1))

## 0 is False but '0' is True
string2 = '00000'
print(all(string2))

## Empty String
string3 = ''
print(all(string3))

```

Output:

```bash
True
True
True

```

## Working of `all()` for dictionaries

```python
## O is False
dict1 = {0: 'False', 1: 'True'}
print(all(dict1))

## All values are true
dict2 = {1: 'True', 2: 'True'}
print(all(dict2))

## One value is False
dict3 = {1: 'True', False: 0}
print(all(dict3))

## Empty dictionary
dict4 = {}
print(all(dict4))

## 0 is False but '0' is True
dict5 = {'0': 'False'}
print(all(dict5))

```

Output:

```bash
False
True
False
True
True

```

In the case of dictionaries, if all keys (not values) are `True` or the dictionary is empty, `all()` returns `True`. Else, it returns `False` for all other cases.

**Note:** 0 is considered as False and 1 is considered as True in Python. In addition to that, '0' is True whereas 0 is False.

## Conclusion

In this part, we learned about the Python `all()` function with the help of examples.